Expansible cutter tool



INVENTOR. I GLENN D JOHNSON ATTORNEY.

Aug. 4, 1936. G. D. JOHNSON EXPANSIBLE CUTTER TOOL Filed Aug. 23, 1933 Patented Aug. 4, 1936:

PATENT OFFlCE EXPANSIBLE CUTTER TOOL Glenn D. Johnson, Compton, CaliL, minor, by mesne assignments, to MacClatchie Manuiac-r turing Company, Compton, Calif a corporation of California Application August 23, 1933, Serial No. 686,379

12 Claims.

dental release of the actuating means until pressure is applied to the hydraulic control.

It is a further'object of the, invention'to completely shut-off the bore of the tool for building up pressure to operate the hydraulic control and thus release the actuating means for operative movement to expand the cutter, with said operative movement of the actuating means adapted to then open the bore of the tool for circulation during the reaming operation of the expanded cutter, and the bore oi. the tool remaining open during subsequent contraction. oi the cutter while withdrawingthe tool from a well.

It is a still further object of the invention to adapt a cutter for operative expansion through direct impingement by a mandrel which is longitudinally shifted by an actuating means, with the construction providingifo'r convenient assembly of at least three equi-distantly circumferentially spaced cutters so as to insure cutting a true circular bore, and the cutters comprising blades which are adapted for vertical swinging to operative position, and which when expanded are adapted for longitudinal thrust against'the body of the tool and lateral thrust against pivot pins upon which the blades are respectively mounted.

Further objects .ofthe invention will be readily understood from the following-description of the accompanying-drawing, in which: Fig. 1 is a side elevation of the tool, partly in axial section, and showing the cutter blades in normal contracted position while lowering the tool into a well.

Fig.2 is a similar view, showing the blades operatively expanded.

The construction embodying the invention is shown as including a cutter support and acylinder for a hydraulic control, withsaid elements fool-proof structure, with nopossibllity of acci- Fig. 3 is a similar view, showing contraction of the blades during withdrawal of the tool from forming a'flxed section of a drill string. The cutter support comprises a body I having a bore 2, and a bit 3 is adapted for suspension from the body, as for'example by a usual threaded connection 4, with the bore 5 of the bit communicating with the bore 2. 4 For convenience of assembly the cylinder 6 for the hydraulic control is prei'erably formed in a. sub i which is detachably mounted on body I by means of a usual threaded connection I; and the cylinder sub is adapted for suspension from a usual tool string (not shown),

, asior example by a threaded pin 8.

The body I is adapted to support a plurality of cutters, which may comprise at least three equidistantly spaced cutters soas to insure cutting a true circular bor'e. For this purpose the cutters, which are shown as blades 9, are respectively mounted in radial slots ill in the body I, with the periphery of the body preferably radially bulged at each slot as shown at l I so as to insure a sturdy construction. The cutter blades are shown pivoted on pins l2 so that they are adapted to swing downwardly into the slots ill for con.-

traction within the body of the tool, or are adapted to be swung outwardly and upwardly for op- 5 erative expansion projecting radially from the body. When the blades are expanded, as shown at Fig. 2, the upper ends of slots ii) are engaged by the. blades so as to take longitudinal thrust, I

and the pivot plus I 2 take the lateral thrust. The v cent pins as shown at Fig. 4, with the washers bolted oncbody l as shown at l5.

The cutter blades are swung to operative position by a common actuatingmeansgwhich is, shown as a mandrel l5 slidable in bore 2 and having a spring ll tending to depress the mandrel. The slots i0 open into bore 2, and a collar I8 is formed on the mandrel and is adapted to engage cooperating notchesv ill in the blades 9 when the mandrel is depressed, so that downward movement 01' the mandrel swings the blades from the position shown at Fig. 1 to that shown at Fig. 2, and during subsequent withdrawal of the tool the blades are free to swing downwardly into slots III, by elevating the mandrel from the position shown at Fig. 2 to that shown at Fig. 3. The spring I! encircles the upper portion of the mandrel and is received in the upper portion oi bore 2, with a bushing 20 threaded into the upper end of the bore and forming an abutment for the upper end of the spring, and a 55 collar 2| 'onthe mandrel iorms abutment for tion, the mandrel I6 is normally held in elevated.

position against the action 01' its spring, so that the cutter blades are free to contract as shown at Fig. 1; and a hydraulic control is adapted to release the mandrel so that the spring ll may depress the mandrel for expanding the cutters. As an instance of this arrangement a shear pin 22 is mounted in a radial bore 23 in body I and extends into a groove 24 in the collar 2|, thereby normallylocking the mandrel against movement; and when the cutter blades are to be expanded hydraulic pressure is developed in cylinder 6 and is exerted against the mandrel i'or shearing-oil? the pin 22 so that the mandrel is ireeior operative depression by its spring II.

For the purpose of such hydraulic control, the upper end oi? mandrel I 6 projects through the bushing 2| into the cylinder 6, and a piston 25 is fixed on the mandrel and is adapted for fluid .tight sliding flt in the cylinder.

The upper end of the cylinder communicates with a bore-2i which opens thro h the upper end or the sub I and which is in turn adapted for communication with the circulating bore of the tool string from which' the under-reamer is suspended; and when the cutter blades are to be expanded fluid is pumped downwardly through the bore of the tion past the cutters when they have been opfluid pumped through the drill string cannot es-' eratively expanded; and for this purpose the mandrel It has a bore opening therethrough, and a wash pipe 21 having an open bore is suspended from the mandrel and has lateral outlet ports 28 below the respective cutter blades; After the fluid which is pumped through the bore of the drill string has built up pressure in cylinder 6 for operating the hydraulic control, the

fluid is permitted to flow through the bore of mandrel l6 and thence through wash pipe 21. A part of the fluid is discharged at the ports 28 adjacent the cutting edges of the expanded blades, and the remainder of the fluid flows from the wash pipe through the bore of'bit 2, for discharge at .the blades of the bit in accordance with usual practice.

As an instance of this arrangement a nippleprojects upwardly from piston '25 and communicates with the bore of the mandrel; but the bore of 'the nipple is closed to the cylinder 6 and to the bore 26 when the cutter blades-are normally contracted as shown at Fig. 1, so that cape via the nipple but must build up pressure in cylinder 6 for releasing the actuating means to expand the cutters by'longitudinal movement of the mandrel. As a result of this movement of themandrel, the bore of nipple "is opened to cylinder 6 so .that fluid is free to circulate through the bore of thetool. a valve seat 3| is formedv at the upper end of the bore of the nipple, and a ball valve 22 is adapted'to engage this seat and closethe bore' of the nipple when the partsare in normal position as shown at Fig. 1, but when the mandrel and the nipple have been depressed asshown at drill string. i

Forthispurpose Fig. 2, the ball valve is engaged by an abutment in the bore 26, so that it is held in spaced relation above its seat ll, thereby opening the bore of the nipple to the cylinder 6. The abutment for the ball valve is shown as a spider 33 having 5 fluid eways 24, whereby the .bore 26 remains open to cylinder 8 both when the ball valve engages its seat and when it is supported on the spider.

In operation, the tool is run into a well on ausual drill string, with the cutters contracted as shown at Fig. 1 and the mandrel l6 held in inoperative position by the shear pin 22. The ball valve 32 is free to rise' i'rom its seat 3| so as to open the bore of the tool, the movement 15 of the ball valve being limited by a stop pin 40. when the tool is-below the well casing and at the level at whichit is desired to expand the cutters, pump pressure is applied to fluid in the drill string, thereby seating the ball valve and 20 closing the bore of nipple Ill so that fluid pressure is built up in cylinder 6. This pressure actuates piston 25 as shown at Fig. 2, so as to shear on the pin 22, thereby depressing mandrel l6 by its spring I! for expanding the cutter 25 bladeaand unseating the ball valve 22 for circulation through the bore of the tool. The drill string is then rotated for. cutting action by the expanded cutter blades. when the tool is to be withdrawn from the well the blades are contracted as shown at Fig. 3, through abutment of their upper edges against the endof the well casing, and the mandrel I6 is thus elevated slightly against the tension of its spring 11, but with the valve seat 3| still spaced from the ball valve 22 so that the bore of the tool remains open. Before the under-reamer is again run into a well,

a suitable tool is inserted through a slot ll in the body I, for engaging the collar 2| to again elevate the mandrel ii to a position where a new 40 shear pin may be inserted in bore 23 for rengagthe bore of the tool is adapted to be completely closed to insure pressure being built up for operating the'hydraulic control, but when the cutters have been expanded the bore of the tool is opened for circulating a washing medium during the reaming operation, and during withdrawal of the tool its bore remains open for bleeding the The cutters 9 and the slots ID are preferably arranged so that the slots while of restricted size I Theslde edge to of the blade portion of each cutto the longitudinal axis of the tool when the cutter forms an angular continuation of the side edge 9b of the shank of the cutter, and the opposite side edge 90 of the blade forms. an annular continuation of the side edge 9d of the shank, with the side edges 9a-9c slanting toward one another and connected by a blade edge 9e.

- The pivot pin i2 extends through the shank portion of the cutter adjacent its end which is remote from the projecting blade portion of the cutter, and the pivot pin is mounted in slot i9 adjacent its upper end. The shank portion of the cutter may be of appreciable width for desired strength while still providing for its complete reception within the slot I0 when the cutter is con-- tracted and the shank portion of the cutter is received within the full width of slot Ill above its slanting lower end lob as shown at Fig. l. The blade portion of the cutter may also be of appreciable width to obtain desired strength of the blade and to provide a blade edge 9c of substantial length, and it may be appreciably elongated for desired length of its blade edge 9c while still providing for complete reception of the blade portion of the cutter within the lower portion of slot l0, since the angular disposition of blades edges 9a-9c adapts the blade portion of the cutter for complete reception within the tapering lower por tion of slot l0 which is defined by the slanting end wall |0b as shown at Fig. l. The steep inclination of the slanting end wall lllb insures a substantial width for said tapering lower portion of the slot along an appreciable length thereof, and thus provides for reception of a blade portion of the cutter which is of appreciable length and Width. vAt the same time the slot l0 is.maintained of restricted size so as not to unduly weaken the body of the tool. When the cutter is expanded its shank edge 9b engages the end wall Illa of the slot, the inclination of the end wall Hla being such as to horizontally position the blade edge 90 and to vertically position the blade edge 9e when the cutter is expanded as shown at Fig. 2, so that blade edge 90 provides a horizontal cut ting edge projecting appreciably beyond bulge II and blade edge 90 provides a reaming edge of appreciable length.

When the cutters have been operatively project'ed they are held in expanded position by the formation pressing against the pivoted blades so that the shank edges 9b abut the end walls la; and with the parts in this position the. collar I8 is preferably adapted for slight vertical play relative to notches I9, so that vibration of mandrel I 6 resulting from pulsation of the pump which circulates the washing medium, will riot cause excessive wear of the collar against the walls of the notches. For this purpose collar l9 and notches I9 are of such relative width that when the cutters are in expanded position slight clearance l9a is provided between the collar and the walls of the notches as shown at Fig. 2.

It will be noted that the cutters, while of somewhat irregular outline, have a well defined greater .length than width as viewed inside elevation, with the width of each cutter defined generally by the distance between the edges Bar-9b at one side of the elongated cutter and the edges 9c-9d at its opposite side, and with the greater length of the cutterdefined generally by the distance between the edge 9e at the outer end of the cutter and that edge of the cutter which is notched at 19 and which is at the inner end of the cutter at the op-- posite side of pivot l2. Such generallydefined length of the cutter is substantially perpendicular erally defined length or the cutter is approximate- -ly horizontal, i. e. perpendicular to the longiter isexpanded as shown at Fig. 2, and extends in the general direction of the longitudinal axis of the tool when thecutter is contracted as shown at Fig. 1. In other words the cutting edge 90 is approximately parallel to the generally defined length of the cutter, so that when the cutter is in operative position with its cutting edge c hori-, zontal and its cutting edge 9e vertical, the gen-'10 tudinai axis of the tool, and when the cutter is contracted its edge 90 slants upwardly and inwardly at a steep angle, so that the lower edge lb of the slot It] may have a similar steep incli- 1 nation andstill provide a'slot which will accommodate the contracted cutter. Consequently the expanded cutter provides maximum cutting gauge for its length, and the contracted cutter is received within a slot which produces only minimum weakening of the body of the tool.

I claim:

1. In combination, a hollow support having a radial slot, a cutter pivoted in the slot and adapted to swing upwardly and outwardly to expand- 25 ed position leaving an unobstructed lower portion of the radial slot below the expanded cutter, and a hollow mandrel movable in the bore of ,the hollow support and engaging the cutter for-swinging the same, the hollow mandrel being adapted for flow of drilling fluid therethrough for discharge from the lower end of the mandrel into the bore of the hollow support below the radial slot and having a lateral port in its side wall. for discharge of a portion of said flow of drilling fluid, the lateral port being positioned above the lower end of the mandrel for substantial 'transverse alinement with said lower unobstructed portion of the radial slot when the mandrel has moved to a position 40 expanding the cutter.

2. In combination, a hollow body. an expansible cutter, the body being of fixed length and having means for mounting it between upper and lower portions of a drill string and holding 45 it against/longitudinal movement relative to said portions of the string during expansion of the v spring tending to move the mandrel in the direction for expanding the cutter, a sheer pin cooperating withthe mandrel for holding 'it against said movement, and means for exerting fluid pressure against the mandrel for shearing oiI the 55 pin.

3. In combination, a body, an expansible cutter, the body being of .fixed length and having means for mounting it between upper. and lower portions or a drill :string and holding it against longitudinal movement relative to said portions of the string during expansion of the cutter, actuating means longitudinally movable relative to the body and the drill string for expanding the cutter, a spring tending to move the actuating means in the direction for expanding the cutter, and-means cooperating with the actuating means for holding it against said movement, said holding meansbeing arranged whereby it may be rendered inoperative by fluid pressure in the drill string.

longitudinal movement relative to the drill string Y during expansion or the cutter, a mandrel in the hollow body, the mandrel being longitudinally movable relative to the body and the drill string for expanding the cutter, a spring tending to move the mandrel in the direction for expanding the cutter, and means cooperating with the mandrel for holding it against said movement,

' said holding means being arranged whereby it ing means for holding it against said movement,

and means for exerting fluid pressure against the actuating means for shearing oil! the pin.

6. In combination, a hollow body, an expansible cutter,the body having means for suspending it from a drill string and holding it against longitudinal movement relative to the drillstring during expansion of the cutte a mandrel in the hollow body, the mandrel being longitudinally movable relative to the body-and the drill string for expanding the cutter, means tending to move the mandrel in the direction for expanding the cutter, a shear pin cooperating with the mandrel for holding it against said movement, and means for exerting fluid pressure against the mandrel for shearing oi! the pin.

7. In combination, a hollow body, an expansible cutter, the body having means lor suspending it from a drill string and holding it against longitudinal movement relative to the drill string during expansion of the cutter, a mandrel in the hollow body, the mandrel being longitudinally movable relative to the body and the drill string for expanding the cutter, a spring tending to move the mandrel in the direction for, expanding the cutter, a shear pin cooperating with the mandrel for holding it against said movement,

and means for exerting fluid pressure against the mandrel for shearing oi the pin. I

8. In combination a hollowflsupport having a Q radial slot, a cutter adapted for movement in the slot for expanding the cutter and leaving an unobstructed portion of the radial slot longitudinally beyond the expanded cutter, and a hollow mandrel movable in the hollow'support and cooperating with the cutter for expanding the same, the hollow mandrel being adapted to receive drilling fluid and having a lateral outlet for said drilling fluid, the lateral outlet being positioned for substantially transverse discharge into said unobstructed portion of the radial slot when the mandrel cutter.

9. In combination, a hollowsupport having a radial slot, a cutter adapted tor movement in the slot for expanding the cutter, and a hollow mandrel movable in the hollow support and cooperating with the cutter for expanding the same, the hollow mandrel being adapted to receive drilling fluid and having an outlet for said drilling fluid, the outlet being positioned for direct discharge transversely into the radial slot when the mandrel is in positionexpanding the cutter.

is in position expanding the 10. In combination, a hollow support having a slot extending through its wall, the bottom wall of the slot slanting upwardly and inwardly at a relatively steep angle to the support axis, a cutter comprising a shank and a blade, the cutter being of generally elongated form with its side edges which deflne the width of its blade tapering "toward the outer end of the blade and connected at their outer ends by an end cutting edge which deflnes the length of the cutter, one or said side edges or the blade also forming a cutting edge ,at the underside oi the blade which is substantially parallel to the length or the cutter, and pivot'means engaging the shank or the cutter remote from its blade and adjacent an edge or the shank which defines the opposite end of the length or the cutter, said means pivoting the cutter in the slot adjacent the upper end of the slot, the shank of thecutter being adapted for reception within the upper portion of the slot, and 20 the blade oi the cutter being adapted for recep- A tapering lower portion of the slot, the cutter when expanded abutting its shank against the upper wall oi the slot, with the length or the cutter approximately perpendicular to the support axis and with'the cutting edge at the underside of the blade positioned substantially horizontally and projecting an appreciable distance radially beyond the support, and the cutting edge at the end of the blade being vertically disposed and forming a reaming edge of appreciable length.

11. In a reamer, a hollow support having a slot in its wall, the bottom wall or the slot slanting upwardly and inwardly, a cutter comprising a shankand a blade, the cutter being of generally elongated form, one of its side edges which define the width of the blade forming a cutting edge at the underside of the blade which is substantially parallel to the length of the cutter, one of the edges of the cutter which defines its length also forming a cutting edge at the outer end oi the blade, and pivot means adjacent an edge of. the shank which deflnes the opposite end of the length or the cutter, said means-pivoting-the cutter in the slot,rthe shank of the cutter being adapted tor reception within the upper portion ot the slot, and the blade of the cutter being adapted for reception within the lower tapering portion 01 the slot when the cutter is contracted, with the length of the cutter at a slight angle to the 'support'axis and with the cutting edge at the underside of the blade extending along the slanting bottom wall of the slot for an appreciable distance but terminating short of the end of the tapering lower portion of the slot, the cutter when expanded abutting its shank against the upper wall of the slot, with the length or the cutter approximately perpendicular to the support axis and with the cuttingedge at the underside o! the blade positioned, substantially horizonslot in its wall, the bottom wall oithe slot slanting upwardly and inwardly, sputter comprising a shank and a blade, the cutter being 0! generally elongated form, one of its side edges which de- I fine the width of the blade forming a cutting edge at the underside of the blade which is'substantially parallel to the length of the cutter, and

- pivot means adjacent an edge ot'the shank which defines the length oi! the cutter,'said means pivoting' the cutter in the slot, the shank of the cutter being adapted for reception within the upper portion of the slot, and the blade at the cutter being adapted i'or reception within the lower tapering portion 0! the slot when cutter is contracted, with the length of the cutter at a slight angle to the support axis and with the cutting edge oi. the blade'extending along the slanting bottom wall 01' the slot for an appreciable distance, the cutter, when expanded, having the length of the cutter approximately per pendicular to the support axis, 'with the cutting edge substantially horizontal and projectingau appreciable distance radially beyond the support. 10

' GLENN n.- JOHNBON. 

